This proposal seeks renewal for UCLA's predoctoral Cellular and Molecular Biology Training Program. Now in its 26th year, the program has trained more than 350 Ph.D. candidates for careers in biomedical research and education. The program is interdepartmental and includes faculty and students in the Departments of Chemistry and Biochemistry and Molecular, Cell and Developmental Biology in the College of Letters and Sciences, the Departments of Biological Chemistry, Microbiology, Immunology and Molecular Genetics, and Neurobiology in the School of Medicine, as well as the Interdepartmental Program in Molecular Biology. There are currently 84 training faculty with primary appointments in 10 departments. Major research areas include biochemistry, cell biology, developmental biology, gene expression, macromolecular structure, molecular and cellular immunology, neurobiology, virology and microbial pathology. Representatives of each of the six major Ph.D. degree programs involved nominate trainees for the program. Students are selected on a highly competitive basis using the criteria of their academic and research achievements. Appointments are made for a maximum period of three years. A small number of students enter the training program as first year students; however, the bulk of them come in after a year of graduate work when they have chosen their dissertation research director. In addition to meeting the University and Departmental or Program requirements for their degrees, trainees participate in a research ethics course, as well as in seminars and conferences organized by the Training Program. This proposal requests stipends for 45 trainees. The facilities are those of a major undergraduate and graduate campus of approximately 33,000 students that includes a medical school faculty. All of the departments involved in this program are in close proximity to each other and to the interdepartmental Molecular Biology Institute, which facilitates interactions of both students and faculty.